ladybird/Libraries/LibGfx/Font/Font.h
Tim Ledbetter 0be802797a LibGfx: Cache font-independent shape data in the font shaping cache
The shaping cache previously stored HarfBuzz buffers keyed by string,
and `shape_text()` rebuilt a fresh `GlyphRun` on every call. Cache the
font-independent shape data instead, so repeated shaping of the same
input skips both the HarfBuzz call and the glyph-vector build.
2026-06-09 17:35:54 +02:00

136 lines
3.9 KiB
C++

/*
* Copyright (c) 2020, Stephan Unverwerth <s.unverwerth@serenityos.org>
* Copyright (c) 2023, MacDue <macdue@dueutil.tech>
* Copyright (c) 2023-2025, Andreas Kling <andreas@ladybird.org>
* Copyright (c) 2025, Aliaksandr Kalenik <kalenik.aliaksandr@gmail.com>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/AtomicRefCounted.h>
#include <AK/FlyString.h>
#include <AK/HashMap.h>
#include <AK/OwnPtr.h>
#include <AK/RefPtr.h>
#include <AK/Utf16String.h>
#include <LibGfx/Font/Font.h>
#include <LibGfx/Font/Typeface.h>
#include <LibGfx/ShapeFeature.h>
class SkFont;
struct hb_font_t;
struct hb_buffer_t;
namespace Gfx {
struct ShapedGlyphs;
struct ShapingCacheKey {
Utf16String text;
u8 text_type { 0 };
u32 letter_spacing_bit_pattern { 0 };
bool operator==(ShapingCacheKey const&) const = default;
};
struct FontPixelMetrics {
float x_height { 0 };
float advance_of_ascii_zero { 0 };
// Number of pixels the font extends above the baseline.
float ascent { 0 };
// Number of pixels the font descends below the baseline.
float descent { 0 };
};
// https://learn.microsoft.com/en-us/typography/opentype/spec/os2#uswidthclass
enum FontWidth {
UltraCondensed = 1,
ExtraCondensed = 2,
Condensed = 3,
SemiCondensed = 4,
Normal = 5,
SemiExpanded = 6,
Expanded = 7,
ExtraExpanded = 8,
UltraExpanded = 9
};
constexpr float text_shaping_resolution = 64;
class Font : public AtomicRefCounted<Font> {
public:
Font(NonnullRefPtr<Typeface const>, float point_width, float point_height, FontVariationSettings const variations, ShapeFeatures const& features);
~Font();
u64 id() const { return m_id; }
float point_size() const;
float pixel_size() const;
FontPixelMetrics const& pixel_metrics() const { return m_pixel_metrics; }
u8 slope() const { return m_typeface->slope(); }
u16 weight() const { return m_typeface->weight(); }
bool contains_glyph(u32 code_point) const { return m_typeface->glyph_id_for_code_point(code_point) > 0; }
float glyph_width(u32 code_point) const;
u32 glyph_id_for_code_point(u32 code_point) const { return m_typeface->glyph_id_for_code_point(code_point); }
int x_height() const { return m_point_height; } // FIXME: Read from font
float width(Utf16View const&) const;
FlyString const& family() const { return m_typeface->family(); }
NonnullRefPtr<Font> with_size(float point_size) const;
Typeface const& typeface() const { return m_typeface; }
SkFont skia_font(float scale) const;
Font const& bold_variant() const;
hb_font_t* harfbuzz_font() const;
FontVariationSettings const& variation_settings() const { return m_font_variation_settings; }
ShapeFeatures const& features() const { return m_shape_features; }
struct ShapingCache {
HashMap<ShapingCacheKey, OwnPtr<ShapedGlyphs>> map;
OwnPtr<ShapedGlyphs> single_ascii_character_map[128];
~ShapingCache();
void clear();
};
ShapingCache& shaping_cache() const { return m_shaping_cache; }
bool is_emoji_font() const;
private:
u64 m_id { 0 };
mutable RefPtr<Font const> m_bold_variant;
mutable hb_font_t* m_harfbuzz_font { nullptr };
mutable ShapingCache m_shaping_cache;
mutable TriState m_is_emoji_font { TriState::Unknown };
NonnullRefPtr<Typeface const> m_typeface;
float m_point_width { 0.0f };
float m_point_height { 0.0f };
FontVariationSettings const m_font_variation_settings;
ShapeFeatures m_shape_features;
FontPixelMetrics m_pixel_metrics;
float m_pixel_size { 0.0f };
};
}
namespace AK {
template<>
struct Traits<Gfx::ShapingCacheKey> : public DefaultTraits<Gfx::ShapingCacheKey> {
static unsigned hash(Gfx::ShapingCacheKey const& key)
{
return pair_int_hash(key.text.hash(), pair_int_hash(key.text_type, key.letter_spacing_bit_pattern));
}
};
}